The long-term objective of this research continue to be to understand (1) the role of hemodynamics in the localization and development of atherosclerosis, and (2) the extent to which local geometric features of arteries, as mediators of the hemodynamic environment of the vessel wall, influence an individual's susceptibility to vascular disease. These objectives are approached by relating the geometric features of coronary arteries obtained from post-mortem angiograms to the histopathology of the vessels. Angiograms are prepared in multiple planes of the left coronary arteries of autopsy hearts gathered locally and from University of Maryland and Louisiana State University. The hearts are prepared under the established Pathobiological Determinants of Atherosclerosis in Youth (PDAY) protocols. The left main coronary artery, the first 5-8 cm of the left anterior descending artery, the proximal circumflex artery, and the proximal portions of their early branches, are removed from the hearts and characterized with respect to wall thickness, structure, and composition, stainable lipid and lesion distribution by image processing of (1) soft x-ray films of entire vessels and (2) selected transverse sections prepared with histological stains of immunocytochemical markers. The soft x-ray imaging and histotechnique will be performed at the University of Illinois at Chicago. The multiplane angiograms are processed, using objective computerized algorithms, to reconstruct the course of the axes of the segments of interest in three-space. A Second set of objective algorithms is then applied to these geometries to obtain quantitative geometric parameters of the segments (e.g., branch angles, branch asymmetry, distances between branch points and other landmarks, and tortuosity). The relation among these parameters, the morphology and pathology of the specimens, and the subjects' risk factor profiles will be examined in detail using appropriate statistical techniques. An understanding of the relation between arterial geometry and the predisposition to atherosclerosis can improve the productivity of epidemiological studies and suggest "geometric risk factors" that may predict an individuals susceptibility to atherosclerosis at specific sites. The known effects of geometry on local flow fields will be used to draw inferences regarding the role of hemodynamics in relation to human atherogenesis.